248
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
10 Arithmetic and Logical Operation (
+
,
−
,
×
,
÷
) – FNC 20 to FNC 29
10.1 FNC 20 – ADD / Addition
Program example
1. Difference between ADD instruction and INC instruction caused by a program for adding
"+1"
When ADD[P] is executed, "1" is added to the contents of D0 every time X001 turns ON from OFF.
ADD[P] instruction is similar to INCP instruction described later except the contents shown in the table below:
ADD, ADDP, DADD or DADDP
instruction
INC, INCP, DINC, DINCP instruction
Flag (zero, borrow or carry)
Operates
Does not operate
O
perat
ion r
e
sult
16-bit
operation
+(+1)=
+32767
→
0
→
+1
→
+2
→
+32767
→−
32768
→−
32767
+(
−
1)=
←−
2
←−
1
←
0
←−
32768
⎯
32-bit
operation
+(+1)=
+2,147,483,647
→
0
→
+1
→
+2
→
+2,147,483,647
→−
2,147,483,648
→−
2,147,483,7
+(
−
1)=
←−
2
←−
1
←
0
←−
2,147,483,648
⎯
S
D
S
D
S
D
S
D
FNC 20
ADDP
D 0
K 1
D 0
X001
(D 0) + 1
→
(D 0)
FNC 24
INCP
D 0
X001
(D 0) + 1
→
(D 0)
S
1
S
2
D